Infrared photoconduction in radiation-damaged silicon diodes

The photoconductive property in silicon p-i-n diodes irradiated with 1 MeV neutrons has been investigated in the infrared band using current and capacitance measurements. This property is demonstrated to be affected by the presence of radiation-induced defect centres in the band gap. The measurements show that an increase in fluence leads to a marked decrease in photocurrent. It is argued that an increase in light intensity may increase the effective carrier density but the density of electron-hole pairs contributing to the total measured current is reduced by an increase in the number of radiation-induced generation-recombination centres.